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Chenebault C, Percheron B. Development of a simple and versatile process for commercial and municipal lignocellulosic waste conversion into fermentable sugars. BIORESOURCE TECHNOLOGY 2023; 386:129497. [PMID: 37473788 DOI: 10.1016/j.biortech.2023.129497] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Revised: 07/11/2023] [Accepted: 07/13/2023] [Indexed: 07/22/2023]
Abstract
Lignocellulosic wastes are valuable feedstock in biorefinery thanks to their high sugars content and low level of fibers intricacy. However, their massification is often a limiting parameter in the development of industrial projects. Hence, this study aims to develop an efficient process enabling the conversion of several waste streams within the same process line. Several pretreatment and enzymatic hydrolysis parameters were firstly evaluated with Old Corrugated Cardboards (OCC) as a model substrate. A chemical free pretreatment followed by an enzymatic hydrolysis (Cellic Ctec 3 enzymatic cocktail at 0.06 g of cocktail per g of Total Sugars (TS)) efficiently depolymerized OCC into monomeric sugars (0.50 g/gTS) consequently fermented into ethanol (0.24 g/gTS). Then, the suitability of this process was validated for sugars production from Pulp and Paper (P&P) sludge (0.48 g/gTS), sieved toilets papers (0.40 g/gTS), the Organic fraction of municipal solid waste (0.37 g/gTS) and Waste Wood B (0.08 g/gTS).
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2
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Characterization of a novel bifunctional enzyme from buffalo rumen metagenome and its effect on in vitro ruminal fermentation and microbial community composition. ANIMAL NUTRITION 2023; 13:137-149. [PMID: 37123618 PMCID: PMC10130076 DOI: 10.1016/j.aninu.2023.01.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2022] [Revised: 12/26/2022] [Accepted: 01/09/2023] [Indexed: 01/15/2023]
Abstract
To efficiently use lignocellulosic materials in ruminants, it is crucial to explore effective enzymes, especially bifunctional enzymes. In this study, a novel stable bifunctional cellulase-xylanase protein from buffalo rumen metagenome was expressed and characterized, CelXyn2. The enzyme displayed optimal activity at pH 6.0 and 45 °C. The residual endoglucanase and xylanase activities were 90.6% and 86.4% after a 60-min pre-incubation at 55 °C. Hydrolysis of rice straw, wheat straw, sheepgrass and sugar beet pulp by CelXyn2 showed its ability to degrade both cellulose and hemicellulose polymers. Treatment with CelXyn2 improved the hydrolysis of agricultural residues with an evident increase in production of total gas, lactate and volatile fatty acids. The results of 16S rRNA and real-time PCR showed that the effect on in vitro ruminal microbial community depended on fermentation substrates. This study demonstrated that CelXyn2 could strengthen lignocellulose hydrolysis and in vitro ruminal fermentation. These characteristics of CelXyn2 distinguish it as a promising candidate for agricultural application.
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Kellner N, Griesel S, Hurt E. A Homologous Recombination System to Generate Epitope-Tagged Target Genes in Chaetomium thermophilum: A Genetic Approach to Investigate Native Thermostable Proteins. Int J Mol Sci 2022; 23:ijms23063198. [PMID: 35328616 PMCID: PMC8951082 DOI: 10.3390/ijms23063198] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2022] [Revised: 03/10/2022] [Accepted: 03/14/2022] [Indexed: 11/16/2022] Open
Abstract
Chaetomium thermophilum is an attractive eukaryotic model organism which, due to its unusually high temperature tolerance (optimal growth at 50-52 °C), has a thermostable proteome that can be exploited for biochemical, structural and biotechnological applications. Site directed gene manipulation for the expression of labeled target genes is a desirable approach to study the structure and function of thermostable proteins and their organization in complexes, which has not been established for this thermophile yet. Here, we describe the development of a homologous recombination system to epitope-tag chromosomal genes of interest in Chaetomium thermophilum with the goal to exploit the derived thermostable fusion proteins for tandem-affinity purification. This genetic approach was facilitated by the engineering of suitable strains, in which factors of the non-homologous end-joining pathway were deleted, thereby improving the efficiency of homologous integration at specific gene loci. Following this strategy, we could demonstrate that gene tagging via homologous recombination improved the yield of purified bait proteins and co-precipitated factors, paving the way for related studies in fundamental research and industrial applications.
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Affiliation(s)
| | | | - Ed Hurt
- Correspondence: (N.K.); (E.H.)
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Hu Y, Li H, Ran Q, Liu J, Zhou S, Qiao Q, Song H, Peng F, Jiang Z. Effect of carbohydrate binding modules alterations on catalytic activity of glycoside hydrolase family 6 exoglucanase from Chaetomium thermophilum to cellulose. Int J Biol Macromol 2021; 191:222-229. [PMID: 34508724 DOI: 10.1016/j.ijbiomac.2021.09.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Revised: 09/01/2021] [Accepted: 09/01/2021] [Indexed: 12/31/2022]
Abstract
Exoglucanase (CBH) is the rate limiting enzyme in the process of cellulose degradation. The carbohydrate binding module (CBM) can improve the accessibility of cellulase to substrate, thereby promoting the enzymatic hydrolysis of cellulase. In this study, the influence of CBM on the properties of GH6 exoglucanase from Chaetomium thermophilum (CtCBH) is systematically explored from three perspectives: the fusion of exogenous CBM, the exogenous CBM replacement of its own CBM, and the deletion of its own CBM. The parental and reconstructed CtCBH presented the same optimum pH (6.0) and temperature (60 °C) for maximum activity. Fusion of exogenous CBM increased the binding capacity of CtCBH to Avicel by 8% and 9%, respectively, but it had no significant effect on its catalytic activity. The exogenous CBM replacement of its own CBM resulted in a 12% reduction in the binding ability of CtCBH to Avicel, and a 26% reduction in the catalytic activity of Avicel. The deletion of its own CBM significantly reduced the binding ability of CtCBH to Avicel by approximately 53%, but its catalytic activity was not obviously reduced. These observations suggest that binding ability of CBM is not necessary for the catalysis of CtCBH.
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Affiliation(s)
- Yanmei Hu
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Hubei University, Wuhan 430062, PR China; Hubei Key Laboratory of Industrial Biotechnology, School of Life Science, Hubei University, Wuhan 430062, PR China
| | - Huanan Li
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Hubei University, Wuhan 430062, PR China; Hubei Key Laboratory of Industrial Biotechnology, School of Life Science, Hubei University, Wuhan 430062, PR China
| | - Qiuping Ran
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Hubei University, Wuhan 430062, PR China; Hubei Key Laboratory of Industrial Biotechnology, School of Life Science, Hubei University, Wuhan 430062, PR China
| | - Jiashu Liu
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Hubei University, Wuhan 430062, PR China; Hubei Key Laboratory of Industrial Biotechnology, School of Life Science, Hubei University, Wuhan 430062, PR China
| | - Shanna Zhou
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Hubei University, Wuhan 430062, PR China; Hubei Key Laboratory of Industrial Biotechnology, School of Life Science, Hubei University, Wuhan 430062, PR China
| | - Qiming Qiao
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Hubei University, Wuhan 430062, PR China; Hubei Key Laboratory of Industrial Biotechnology, School of Life Science, Hubei University, Wuhan 430062, PR China
| | - Huiting Song
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Hubei University, Wuhan 430062, PR China; Hubei Key Laboratory of Regional Development and Environmental Response, Faculty of Resources and Environmental Science, Hubei University, Wuhan 430062, PR China
| | - Fang Peng
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Hubei University, Wuhan 430062, PR China; Hubei Key Laboratory of Regional Development and Environmental Response, Faculty of Resources and Environmental Science, Hubei University, Wuhan 430062, PR China
| | - Zhengbing Jiang
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Hubei University, Wuhan 430062, PR China; Hubei Key Laboratory of Industrial Biotechnology, School of Life Science, Hubei University, Wuhan 430062, PR China.
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5
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Singh A, Schermann G, Reislöhner S, Kellner N, Hurt E, Brunner M. Global Transcriptome Characterization and Assembly of the Thermophilic Ascomycete Chaetomium thermophilum. Genes (Basel) 2021; 12:1549. [PMID: 34680944 PMCID: PMC8535861 DOI: 10.3390/genes12101549] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2021] [Revised: 09/24/2021] [Accepted: 09/26/2021] [Indexed: 12/30/2022] Open
Abstract
A correct genome annotation is fundamental for research in the field of molecular and structural biology. The annotation of the reference genome of Chaetomium thermophilum has been reported previously, but it is essentially limited to open reading frames (ORFs) of protein coding genes and contains only a few noncoding transcripts. In this study, we identified and annotated full-length transcripts of C. thermophilum by deep RNA sequencing. We annotated 7044 coding genes and 4567 noncoding genes. Astonishingly, 23% of the coding genes are alternatively spliced. We identified 679 novel coding genes as well as 2878 novel noncoding genes and corrected the structural organization of more than 50% of the previously annotated genes. Furthermore, we substantially extended the Gene Ontology (GO) and Enzyme Commission (EC) lists, which provide comprehensive search tools for potential industrial applications and basic research. The identified novel transcripts and improved annotation will help to understand the gene regulatory landscape in C. thermophilum. The analysis pipeline developed here can be used to build transcriptome assemblies and identify coding and noncoding RNAs of other species.
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Affiliation(s)
| | | | | | | | | | - Michael Brunner
- Heidelberg University Biochemistry Center (BZH), Im Neuenheimer Feld 328, D-69120 Heidelberg, Germany; (A.S.); (G.S.); (S.R.); (N.K.); (E.H.)
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Carrasco J, García‐Delgado C, Lavega R, Tello ML, De Toro M, Barba‐Vicente V, Rodríguez‐Cruz MS, Sánchez‐Martín MJ, Pérez M, Preston GM. Holistic assessment of the microbiome dynamics in the substrates used for commercial champignon (Agaricus bisporus) cultivation. Microb Biotechnol 2020; 13:1933-1947. [PMID: 32716608 PMCID: PMC7533343 DOI: 10.1111/1751-7915.13639] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Accepted: 07/09/2020] [Indexed: 11/30/2022] Open
Abstract
Microorganisms strongly influence and are required to generate the selective substrate that provides nutrients and support for fungal growth, and ultimately to induce mushroom fructification under controlled environmental conditions. In this work, the fungal and bacterial microbiota living in the different substrates employed in a commercial crop (compost phase I, II and III, flush 1 and 2, and casing material on day 1, 6 and 8 after compost casing and during flush 1 and 2) have been characterized along the different stages of cultivation by metataxonomic analysis (16S rRNA and ITS2), analysis of phospholipid fatty acid content (PLFAs) and RT-qPCR. Additionally, laccase activity and the content of lignin and complex carbohydrates in compost and casing have been quantified. The bacterial diversity in compost and casing increased throughout the crop cycle boosted by the connection of both substrates. As reflected by the PLFAs, the total living bacterial biomass appears to be negatively correlated with the mycelium of the crop. Agaricus bisporus was the dominant fungal species in colonized substrates, displacing the pre-eminent Ascomycota, accompanied by a sustained increase in laccase activity, which is considered to be a major product of protein synthesis during the mycelial growth of champignon. From phase II onwards, the metabolic machinery of the fungal crop degrades lignin and carbohydrates in compost, while these components are hardly degraded in casing, which reflects the minor role of the casing for nourishing the crop. The techniques employed in this study provide a holistic and detailed characterization of the changing microbial composition in commercial champignon substrates. The knowledge generated will contribute to improve compost formulations (selection of base materials) and accelerate compost production, for instance, through biotechnological interventions in the form of tailored biostimulants and to design environmentally sustainable bio-based casing materials.
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Affiliation(s)
- Jaime Carrasco
- Department of Plant SciencesUniversity of OxfordS Parks RdOxfordOX1 3RBUK
- Centro Tecnológico de Investigación del Champiñón de La Rioja (CTICH)AutolSpain
| | - Carlos García‐Delgado
- Departamento de Geología y GeoquímicaUniversidad Autónoma de MadridMadridSpain
- Institute of Natural Resources and Agrobiology of Salamanca (IRNASA‐CSIC)SalamancaSpain
| | - Rebeca Lavega
- Centro Tecnológico de Investigación del Champiñón de La Rioja (CTICH)AutolSpain
| | - María L. Tello
- Centro Tecnológico de Investigación del Champiñón de La Rioja (CTICH)AutolSpain
| | - María De Toro
- Plataforma de Genómica y BioinformáticaCentro de Investigación Biomédica de La Rioja (CIBIR)LogroñoSpain
| | - Víctor Barba‐Vicente
- Institute of Natural Resources and Agrobiology of Salamanca (IRNASA‐CSIC)SalamancaSpain
| | | | | | - Margarita Pérez
- Centro Tecnológico de Investigación del Champiñón de La Rioja (CTICH)AutolSpain
| | - Gail M. Preston
- Department of Plant SciencesUniversity of OxfordS Parks RdOxfordOX1 3RBUK
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Han C, Yang R, Sun Y, Liu M, Zhou L, Li D. Identification and Characterization of a Novel Hyperthermostable Bifunctional Cellobiohydrolase- Xylanase Enzyme for Synergistic Effect With Commercial Cellulase on Pretreated Wheat Straw Degradation. Front Bioeng Biotechnol 2020; 8:296. [PMID: 32328483 PMCID: PMC7160368 DOI: 10.3389/fbioe.2020.00296] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2019] [Accepted: 03/20/2020] [Indexed: 12/19/2022] Open
Abstract
The novel cellobiohydrolase gene ctcel7 was identified from Chaetomium thermophilum, and its recombinant protein CtCel7, a member of glycoside hydrolase family 7, was heterologously expressed in Pichia pastoris and biochemically characterized. Compared with commercial hydrolases, purified CtCel7 exhibited superior bifunctional cellobiohydrolase and xylanase activities against microcrystalline cellulose and xylan, respectively, under optimal conditions of 60°C and pH 4.0. Moreover, CtCel7 displayed remarkable thermostability with over 90% residual activity after heat (60°C) treatment for 180 min. CtCel7 was insensitive to most detected cations and reagents and preferentially cleaved the β-1,4-glycosidic bond to generate oligosaccharides through the continuous saccharification of lignocellulosic substrates, which are crucial for various practical applications. Notably, the hydrolysis effect of a commercial cellulase cocktail on pretreated wheat straw was substantively improved by its combination with CtCel7. Taken together, these excellent properties distinguish CtCel7 as a robust candidate for the biotechnological production of biofuels and biobased chemicals.
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Affiliation(s)
- Chao Han
- Key Laboratory of Agricultural Microbiology, College of Plant Protection, Shandong Agricultural University, Tai'an, China
| | - Ruirui Yang
- Key Laboratory of Agricultural Microbiology, College of Plant Protection, Shandong Agricultural University, Tai'an, China
| | - Yanxu Sun
- Key Laboratory of Agricultural Microbiology, College of Plant Protection, Shandong Agricultural University, Tai'an, China
| | - Mengyu Liu
- Key Laboratory of Agricultural Microbiology, College of Plant Protection, Shandong Agricultural University, Tai'an, China
| | - Lifan Zhou
- Key Laboratory of Agricultural Microbiology, College of Plant Protection, Shandong Agricultural University, Tai'an, China
| | - Duochuan Li
- Key Laboratory of Agricultural Microbiology, College of Plant Protection, Shandong Agricultural University, Tai'an, China
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Han C, Wang Q, Sun Y, Yang R, Liu M, Wang S, Liu Y, Zhou L, Li D. Improvement of the catalytic activity and thermostability of a hyperthermostable endoglucanase by optimizing N-glycosylation sites. BIOTECHNOLOGY FOR BIOFUELS 2020; 13:30. [PMID: 32127917 PMCID: PMC7045587 DOI: 10.1186/s13068-020-1668-4] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2019] [Accepted: 01/26/2020] [Indexed: 05/23/2023]
Abstract
BACKGROUND Endoglucanase has been extensively employed in industrial processes as a key biocatalyst for lignocellulosic biomass degradation. Thermostable endoglucanases with high catalytic activity at elevated temperatures are preferred in industrial use. To improve the activity and thermostability, site-directed mutagenesis was conducted to modify the N-glycosylation sites of the thermostable β-1,4-endoglucanase CTendo45 from Chaetomium thermophilum. RESULTS In this study, structure-based rational design was performed based on the modification of N-glycosylation sites in CTendo45. Eight single mutants and one double mutant were constructed and successfully expressed in Pichia pastoris. When the unique N-glycosylation site of N88 was eliminated, a T90A variant was active, and its specific activity towards CMC-Na and β-d-glucan was increased 1.85- and 1.64-fold, respectively. The mutant R67S with an additional N-glycosylation site of N65 showed a distinct enhancement in catalytic efficiency. Moreover, T90A and R67S were endowed with extraordinary heat endurance after 200 min of incubation at different temperatures ranging from 30 to 90 °C. Likewise, the half-lives (t 1/2) indicated that T90A and R67S exhibited improved enzyme thermostability at 80 °C and 90 °C. Notably, the double-mutant T90A/R67S possessed better hydrolysis activity and thermal stability than its single-mutant counterparts and the wild type. CONCLUSIONS This study provides initial insight into the biochemical function of N-glycosylation in thermostable endoglucanases. Moreover, the design approach to the optimization of N-glycosylation sites presents an effective and feasible strategy to improve enzymatic activity and thermostability.
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Affiliation(s)
- Chao Han
- Shandong Key Laboratory for Agricultural Microbiology, College of Plant Protection, Shandong Agricultural University, Tai’an, 271018 Shandong China
| | - Qunqing Wang
- Shandong Key Laboratory for Agricultural Microbiology, College of Plant Protection, Shandong Agricultural University, Tai’an, 271018 Shandong China
| | - Yanxu Sun
- Shandong Key Laboratory for Agricultural Microbiology, College of Plant Protection, Shandong Agricultural University, Tai’an, 271018 Shandong China
| | - Ruirui Yang
- Shandong Key Laboratory for Agricultural Microbiology, College of Plant Protection, Shandong Agricultural University, Tai’an, 271018 Shandong China
| | - Mengyu Liu
- Shandong Key Laboratory for Agricultural Microbiology, College of Plant Protection, Shandong Agricultural University, Tai’an, 271018 Shandong China
| | - Siqi Wang
- Shandong Key Laboratory for Agricultural Microbiology, College of Plant Protection, Shandong Agricultural University, Tai’an, 271018 Shandong China
| | - Yifan Liu
- Shandong Key Laboratory for Agricultural Microbiology, College of Plant Protection, Shandong Agricultural University, Tai’an, 271018 Shandong China
| | - Lifan Zhou
- Shandong Key Laboratory for Agricultural Microbiology, College of Plant Protection, Shandong Agricultural University, Tai’an, 271018 Shandong China
| | - Duochuan Li
- Shandong Key Laboratory for Agricultural Microbiology, College of Plant Protection, Shandong Agricultural University, Tai’an, 271018 Shandong China
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Hua C, Li W, Han W, Wang Q, Bi P, Han C, Zhu L. Characterization of a novel thermostable GH7 endoglucanase from Chaetomium thermophilum capable of xylan hydrolysis. Int J Biol Macromol 2018; 117:342-349. [DOI: 10.1016/j.ijbiomac.2018.05.189] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2018] [Revised: 05/01/2018] [Accepted: 05/25/2018] [Indexed: 01/19/2023]
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10
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Han C, Li W, Hua C, Sun F, Bi P, Wang Q. Enhancement of catalytic activity and thermostability of a thermostable cellobiohydrolase from Chaetomium thermophilum by site-directed mutagenesis. Int J Biol Macromol 2018; 116:691-697. [DOI: 10.1016/j.ijbiomac.2018.05.088] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2018] [Revised: 05/14/2018] [Accepted: 05/14/2018] [Indexed: 01/17/2023]
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